The walls are quickly closing in on the users of testosterone replacement therapy in mixed martial arts.

One week after the Nevada Athletic Commission shook up the sport by announcing a total ban on therapeutic use exemptions for the controversial practice, the California State Athletic Commission announced what in effect amounts to a ban.

The commission stated Thursday that the only way a competitor will be able to receive a TUE is through World Anti-Doping Agency standards, a considerably higher threshold than the system which has been in place.

As the rules are hashed out, in the interim, a total ban will be in effect.

"The California State Athletic Commission fully supports the Nevada State [sic] Athletic Commission's decision to eliminate Therapeutic Use Exemptions (TUE) for Testosterone Replacement Therapy (TRT) in boxing and Mixed Martial Arts," CSAC executive director Andy Foster stated in a written release. "California is a strong supporter of anti-doping efforts. As part of California's anti-doping efforts, the Commission recently began the rulemaking process to require meeting World Anti-Doping Agency (WADA) standards as the only way to obtain a TUE for TRT.

"This standard is so high that it is an effective ban except under the most extreme circumstances," Foster continued. "Until the rulemaking process is complete and the regulations are fully adopted, the Commission has a total ban on TRT. California remains committed to protecting the health and safety of athletes and having strict anti-doping standards is one of the ways this is accomplished."

While the NAC is considered the most influential commission in North America, since Las Vegas is the home to the highest volume of major events in both mixed martial arts and boxing, California hosts the biggest overall number of combat sports events, which makes CSAC an important player among commissions.

TRT came to the forefront in MMA after Chael Sonnen was suspended by California after improperly disclosing his usage leading up to his loss to Anderson Silva at UFC 117 in Oakland in 2010. The total ban is the latest in the state's efforts to grapple with the issue; in June, the state put a moratorium on future TUE exemptions while allowing those who already had been approved to keep doing so.